@TanyaS58 Generally node level page config are set only if the data is shared across all the users in the application irrespective of the Access group of the user. They still need an access group because Pega needs a way to know which rules to use, even though there's no logged-in user at that point. Basically node-level uses for integration. 

Node-level data pages are shared, so they can't be editable or savable — to avoid chaos

Hope this helps.